<p>The aviation industry is rapidly evolving with technological advancements, enhancing aircraft efficiency, passenger experience, and sustainability. However, safety remains a critical challenge for adopting innovations. Every aircraft component, including its software, must comply with stringent regulations and undergo rigorous testing. Safety-critical software, such as flight controllers, battery management, and fuel monitoring systems, play a crucial role in aviation safety. Even minor errors or inadequate testing can lead to catastrophic failures, eroding public trust in air travel. To address this, methodologies such as model-based development, real-time testing, and traceability management streamline development, testing, and certification. This research presents an overview of safety-critical software development and verification processes, along with the supporting tools. It further emphasizes system-level verification through hardware-in-the-loop simulations. The study outlines the key stages of the development process while ensuring compliance with regulatory standards, thereby contributing to safer and more efficient aerospace software engineering. In addition to theoretical insights, the research demonstrates the practical application of the proposed toolchain in developing a multilevel battery control system for an electric glider.</p>